1. Field of the Invention
The present invention relates to a method of measuring the insulation resistance of a capacitor and an apparatus for screening characteristics.
2. Description of the Related Art
In general, a capacitor is determined as good or defective by measuring the insulation resistance of the same. When a capacitor is not charged, the insulation resistance thereof can not be measured correctly because of the capacity of the capacitor. Under such circumstances, a method is commonly used wherein a DC voltage is first applied to the capacitor to precharge it and a leakage current (charging current) is measured thereafter to measure the insulation resistance of the capacitor. Obviously, a good part has a low leakage current.
Known conventional methods for measuring insulation resistance include the method of measurement defined in Japanese Industrial Standard JIS-C5102. However, since a current value must be measured on a capacitor which has been sufficiently charged according to this method, a charging time as long as approximately 60 sec. has been required. The need for electronic apparatuses at reduced cost and with improved reliability has resulted in a need for improvement on the production capacity and quality of electronic components such as capacitors. It is totally impossible to satisfy such a need using the conventional method of measurement that requires such a long charging time per capacitor.
It is therefore an object of the present invention to provide a method of measuring the insulation resistance of a capacitor wherein the insulation resistance of a capacitor can be quickly and accurately measured.
It is another object of the present invention to provide an apparatus for screening the characteristics of capacitors wherein a characteristics measuring step and a packing step can be linked to improve operational efficiency and to reduce the size and cost of the facility.